Wheel suspensions in motor vehicles have different bearings and joints in terms of function depending on the requirements. The joints are used, for example, to make possible a relative motion of two components in a plurality of degrees of freedom. Moreover, joint units that possess special damping properties for vibrations introduced via the wheels of the motor vehicle are known as well.
The joint units used in chassis components are predominantly highly stressed safety components, which are designed usually according to the SafeLife principle, i.e., with multiple safety in a reliably operating manner for the entire service life of a motor vehicle. Nevertheless, events or highly unfavorable causal relationships are conceivable, in which total failure of the joint units usually used may occur.
For example, special wear of the bearing shell or of the pivot pin is conceivable, which may occur due to failure of the sealing systems used in such joint units, because dirt or water enters the interior of the joint. Complete separation of the unity between the housing and the pivot pin of the damaged joint unit would be the most serious consequence of such failure of the joint units. Such a case of separation of the essential components of the joint must be ruled out altogether for safety reasons.
Securing units that prevent complete separation of the housing from the pivot pin have become known from the state of the art for preventing such cases, so that a joint thus damaged still has an emergency running function, which offers the possibility for the vehicle to be transferred to the nearest workshop.
For example, DE 10 2004 055 961 A1 discloses a joint unit having the features forming this class, which is provided with a securing unit called a catching device there, in which at least one flexible catching belt or at least one securing strap with a recess is provided, into which recess a catching pin of the housing protrudes in a contactless manner during normal operation. Such a catching device can definitely prevent separation between the housing and the pivot pin, but it is inevitably always arranged in the outer area of the joint unit in question because of its structural dimensions, which are dictated by the design. However, the visual presence of the objectively desirable and necessary securing system causes a joint unit to be subjectively present for the user, which may not necessarily suggest, owing to its special embodiment, the safety of a joint unit, which would be provided with a redundant securing unit invisible from the outside.